A presence system collects real-time presence information about an individual, applies one or more rules that deduce a status of that individual from that information, and then publishes that information to one or more acquaintances of that individual (known as watchers). Although the presence information is typically ascribed to an individual, the presence information is typically received from devices associated with that individual. For example, a computer associated with (and used by) the individual may send a message to the presence system indicating that it is being used by the individual. The presence system thereby implies that the individual is proximate to that computer when the computer indicates it has user interaction.
Presence systems can be based on an Instant Messaging like paradigm where there is typically a single context (for example, logged in or online with a device) and the people who can see each other's presence in that single context are previously known to each other as part of their buddy list system.
Presence systems can also be based on gaming/chat rooms where there is a fixed set of contexts (e.g., a game room or a chat room) and people that join those contexts can see each other. These contexts typically stay for a long period and people can remain anonymous.
Typically, a presence server written for one of the paradigms above cannot be used practically for the other.
FIG. 1 shows one prior art presence system 100. A presence server 102 of system 100 receives presence information 122 relating to an individual 110 from at least one source, such as a device 104 used by individual 110. Individual 110 subscribes to services of presence server 102 and provides rules as to how presence information 122 is handled and published by presence server 102. In FIG. 1, acquaintances 112 and 114 of individual 110 also subscribe to presence server 102 and are authorized by individual 110 to receive published presence information 124 associated with individual 110 (and based upon presence information 122). Specifically, acquaintance 112 utilizes a watcher device 106(1) to receive presence information 124(A) from presence server 102, and acquaintance 114 utilizes a watcher device 106(2) to receive presence information 124(B) from presence server 102. Devices 104 and 106 may represent a device selected from the group including: mobile phones, personal digital assistants (PDAs), smart phones, and personal computers.
In operation, device 104 allows individual 110 to send presence information 122 (such as a current location, and an activity such as working) to presence server 102, which in turn publishes (i.e., sends) presence information 124 to acquaintances 112 and 114, thereby informing them of changes in the status of individual 110. Specifically, devices 106(1) and 106(2) do not request status information 124(A) and 124(B), respectively, from presence server 102, but are notified directly upon changes to the stored presence of individual 110.
Where device 104 represents a mobile phone, an associated service provider (or the phone itself if it includes GPS functionality) may determine a location of device 104 automatically and send this location as presence information 122 to presence server 102. Thus, published presence information 124 may include location information of device 104, which is also assumed to be the location of individual 110.
Presence server 102 may represent similar social networking services, such as Facebook™, where individual 110 describes current activities and feelings for publication to a network of authorized ‘friends’. Presence server 102 may also represent more than one presence server and social networking server that interact to receive and publish presence information.
In conventional presence systems, such as shown in FIG. 1, when presence status of an individual changes, presence information is published only to authorized subscribers (i.e., acquaintances of the individual) of that information. Scalability of conventional presence is poor: the more subscribers to an individual's presence information, the more work is required to publish that information. Presence information of an individual cannot be received without subscribing to that information through the presence server, and being authorized by the individual to receive that information. Presence information is not available to a third party unknown to the individual.
Further, since there are many difference presence systems, certain acquaintances of the individual may subscribe to a different presence system that the one subscribed to by the individual. Often, to overcome this limitation, the individual would subscribe to more than one presence system such that acquaintances would be allowed to receive published presence information from the individual.